IJmuiden Project - Fred Cottaar, José Verbeek, Maarten van Kleinwee & Mars Muusse

(last update: January 01, 2023)

Herring Gull (argenteus) Y.AFM adult, January 2010 - December 2015, IJmuiden, the Netherlands. Picture: Mars Muusse.

Ringed as breeding adult female in breeding season 2009 at Forteiland, IJmuiden - as adult on the nest, May 04 2009 with clutch of 3 eggs. Ringed by Fred Cottaar ringing team.

below: Herring Gull (argenteus) Y.AFM >10CY, December 03 2015, IJmuiden, the Netherlands.

P10 fully grown. Much black on bill. Black on outerweb of P5.

below: Herring Gull (argenteus) Y.AFM >10CY, November 22 2015, IJmuiden, the Netherlands.

P10 growing.

below: Herring Gull (argenteus) Y.AFM >6CY, March 14 2011, IJmuiden, the Netherlands. Picture: Mars Muusse.

Injured right leg?

below: Herring Gull (argenteus) Y.AFM >5CY, December 09 2010, IJmuiden, the Netherlands. Picture: Mars Muusse.

Injured right leg?

below: Herring Gull (argenteus) Y.AFM >5CY, August 24 2010, IJmuiden, the Netherlands. Picture: Mars Muusse.

P10 still old, P6 fully grown.

below: Herring Gull (argenteus) Y.AFM >5CY, August 24 2010, IJmuiden, the Netherlands. Picture: Mars Muusse.

P5 fully grown.

below: Herring Gull (argenteus) Y.AFM >5CY, January 29 2010, IJmuiden, the Netherlands. Picture: Mars Muusse.

The orbital ring is yellow-orange, and there is some black on the bill. Both features are commonly found in western argenteus.

From June to December, adult argentatus undergo a complete moult resulting in so-called "winter plumage". By August, the first neat streaks can be found on the crown and hind-neck. After the complete moult is finished by late autumn, the head will show extensive 'winter streaking', often neat fine streaking in sub-adult argentatus. 
By the end of the complete moult (sometimes mid-January in argentatus), the scapulars, mantle, all the wing-coverts, rectrices and remiges will be replaced. From June onwards, the new plain grey wing-coverts are moulted in, starting with the outermost median coverts.